The use of enzymes in the cleaning and landering industry has been known for many years and commercial concerns continue to develop more active and useful enzymes. Particularly useful enzymes that are used in the laundering and cleaning industries are proteolytic enzymes, lipolytic enzymes and amylolytic enzymes. The desirability of using proteolytic, α-amylolytic and lipolytic enzymes in cleaning compositions is well known. These enzymes are useful for their ability to reduce macromolecules such as proteins, starches and fats into smaller molecules so that they can be readily washed away by detergents and/or water. Specifically, the proteolytic enzymes are useful in breaking down proteins, the α-amylolytic enzymes are useful in breaking down carbohydrates and the lipolytic enzymes are useful in breaking down fats. Detergent compositions containing these enzymes have a wide variety of uses in that they care capable of removing proteinaceous, starchy and fatty stains such as egg stains, blood stains, gravy stains and the like.
Also, liquid detergents are desirable alternatives to dry, granular detergent products. While dry, granular detergents have found wide consumer acceptance, liquid products can be adapted to a wide variety of uses. For example, liquid products can be directly applied to stains and dirty spots on fabrics, without being predissolved in water or other fluid media. Further, a “stream” of liquid detergent can be more easily directed to a targeted location in the wash water or clothing than a dry, granular product. There have been many attempts to formulate liquid, aqueous detergents which include enzymes. Enzymes are very desirable adjuncts in liquid detergents since they are effective at removing stains which may not be cleaned through detergent or oxidative action. These problematic stains include grass stains, fat stains, oil stains, and blood stains, which typically are complex mixtures of various substances such as proteins, fats, and natural coloring agents.
The use of proteases in heavy duty liquid cleaning formulations is complicated by their limited stability in solution. Two processes which limit the shelf-life of a protease in an aqueous liquid detergent are denaturation and autolysis (self-digestion). Considerable efforts have been devoted to the stabilization of enzymes in aqueous liquid detergent compositions, which represent a medium that is problematical for the preservation of enzyme activity during storage and distribution. Denaturation of proteases may be minimized by selection of optimal formulation components such as actives, builders, etc., and conditions such as pH, so that acceptable enzyme stability is achieved. Self-digestion of proteases may be minimized by inclusion of a protease inhibitor. The inhibitor is released from the enzyme upon dilution in the wash and the proteolytic activity is restored.
It is also known that equipment used in numerous industries comes into contact with various contaminants, which can impede the operation of the equipment and otherwise interfere with production. This effects nearly every industry, including, for example, the chemical processing industry, the oil refinery industry, the pulp and paper industry, the glass manufacturing industry, the general manufacturing industry, and the food and beverage industry. Numerous ferrous and non-ferrous metal surfaces, glass mold surfaces, glass surfaces, as well as plastic surfaces, can similarly become contaminated with oils, greases and other hydrophobic contaminants, as well as inorganic contaminants such as soil. These contaminants are often difficult and expensive to remove using conventional cleaning products and methods. A cleaning step is also routinely included in metal and plastic surface finishing. Typically, these surfaces are cleaned before phosphatizing, rust proofing, painting and the like is done to the surface. It is therefore useful to find cleaning compositions which would address all of the above industries.
The prior art is silent regarding cleaning composition comprising at least one surfactant, one or more viable microorganisms and at least one enzyme and having high stability at high pH as taught by the present invention. There is a long felt need, therefore, for cleaning compositions and methods that are efficient, cost effective, biodegradable and otherwise friendly to the environment. Also, there is a continuing need, therefore, for liquid detergents which contain enzymes which are stabilized and exhibit a greater activity over time.